English as a Medium of Instruction (EMI) is expanding rapidly in the world. A growing volume of research has been dedicated to investigating its implementation, with findings that depict a complex picture and suggest that the practicality and effectiveness of EMI are still the subject of debate. However, considerably less attention has been given to understanding EMI in a context where its implementation has been discussed but not yet put into practice. One such context is Algeria, where talks about a possible implementation of EMI have been going on for some time. This study aims to examine the current discourses and attitudes towards the potential implementation of EMI and the language practices in scientific courses in three Algerian universities. The research was conducted in three different universities with the aim of including both ‘centre’ and ‘periphery’ Algerian universities: The University of Annaba, the University of Batna and the University of Oum El Bouaghi. The findings showed that students and teachers were found in favour of the implementation of English instead of French as a medium of instruction, as the former was seen as having internationalisation and instrumental benefits, while the latter was too closely linked to the colonial history of the country. The favourable attitudes towards EMI, however, seem to contrast with the daily classroom reality, where students and teachers make practical choices of using their language repertoire based on the availability of materials, their linguistic background and skills. Classrooms in the three Algerian universities featured fluid and translanguaging practices that cannot be reduced to a monolingual EMI policy. This study also introduces a new model describing EMI in the world, which I call ‘The Spectrum Model.’ Inspired by Braj Kachru’s (1985) Three Circles of English, the Spectrum Model contributes to the understanding of the presence of EMI in the world by combining both the perspective of World Englishes and contextual variables such as colonial history, linguistic makeup and developmental stage of the various countries.